bool value=LOW;
void setup() {
  Serial.begin(9600);
  pinMode(LED_BUILTIN, OUTPUT);
}
void loop() {
  digitalWrite(LED_BUILTIN, HIGH);   // turn the LED on (HIGH is the voltage level)
  value = (0!=(*portOutputRegister( digitalPinToPort(LED_BUILTIN) ) & digitalPinToBitMask(LED_BUILTIN)));
  Serial.println(value);
  delay(1000);                       // wait for a second
  digitalWrite(LED_BUILTIN, LOW);    // turn the LED off by making the voltage LOW
  value = (0!=(*portOutputRegister( digitalPinToPort(LED_BUILTIN) ) & digitalPinToBitMask(LED_BUILTIN)));
  Serial.println(value);
  delay(1000);                       // wait for a second
}